Laboratory Detection and Initial Diagnosis of Monoclonal Gammopathies

CONTEXT.—

The process for identifying patients with monoclonal gammopathies is complex. Initial detection of a monoclonal immunoglobulin protein (M protein) in the serum or urine often requires compilation of analytical data from several areas of the laboratory. The detection of M proteins depends on adequacy of the sample provided, available clinical information, and the laboratory tests used.

OBJECTIVE.—

To develop an evidence-based guideline for the initial laboratory detection of M proteins.

DESIGN.—

To develop evidence-based recommendations, the College of American Pathologists convened a panel of experts in the diagnosis and treatment of monoclonal gammopathies and the laboratory procedures used for the initial detection of M proteins. The panel conducted a systematic literature review to address key questions. Using the Grading of Recommendations Assessment, Development, and Evaluation approach, recommendations were created based on the available evidence, strength of that evidence, and key judgements as defined in the Grading of Recommendations Assessment, Development, and Evaluation Evidence to Decision framework.

RESULTS.—

Nine guideline statements were established to optimize sample selection and testing for the initial detection and quantitative measurement of M proteins used to diagnose monoclonal gammopathies.

CONCLUSIONS.—

This guideline was constructed to harmonize and strengthen the initial detection of an M protein in patients displaying symptoms or laboratory features of a monoclonal gammopathy. It endorses more comprehensive initial testing when there is suspicion of amyloid light chain amyloidosis or neuropathies, such as POEMS (polyneuropathy, organomegaly, endocrinopathy, M protein, and skin changes) syndrome, associated with an M protein.

Reflexing Suspicious β-Region Findings on Capillary Serum Protein Electrophoresis to Immunofixation or Immunosubtraction for Detecting Monoclonal Proteins

OBJECTIVES

Monoclonal immunoglobulins (M-proteins) that migrate in the β region on serum protein electrophoresis (SPEP) are often cloaked by this region's normal constituents. The present study interrogates the utility of using both quantitative and qualitative alterations in β-region bands for detection of β-migrating M-proteins.

METHODS

Consecutive SPEP cases analyzed by capillary electrophoresis were searched to identify the initial workup on 1,841 patients with increased total β regions, suspicious β-region findings resulting in reflex immunofixation (IFE), or immunosubtraction (ISUB). To augment quantitative information, separate β1 and β2 measurements were established and retrospectively used to evaluate their sensitivity for M-protein detection.

RESULTS

We identified M-proteins in 205 (11.1%) cases, including immunoglobulin A (IgA) (54%), IgG (24%), IgM (13%), and free light chain (9%) isotypes. Of the 15 cases flagged by separate β1 and β2 measurements that were not identified by total β-region measurement, 1 progressed to myeloma. Of the 56 β-migrating M-proteins identified by qualitative features but without increase in any of the β-region measurements, 1 progressed to myeloma.

CONCLUSIONS

A combination of separate measurements for β1 and β2 regions together with detection of β-region distortions increase sensitivity for identifying β-migrating M-proteins via reflex IFE or ISUB.

Implementation of INHERET, an Online Family History and Cancer Risk Interpretation Program for Primary Care and Specialty Clinics

BACKGROUND

Individuals at increased risk for cancer are ascertained at low rates of 1% to 12% in primary care (PC). Underserved populations experience disparities of ascertainment, but data are lacking. INHERET is an online personal and family history tool to facilitate the identification of individuals who are eligible, according to guidelines, to be counseled on germline genetic testing and risk management.

PATIENTS AND METHODS

INHERET data entry uses cancer genetics clinic questionnaires and algorithms that process patient data through NCCN Clinical Practice Guidelines in Oncology and best practice guidelines. The tool was tested in silico on simulated and retrospective patients and prospectively in a pilot implementation trial. Patients in cancer genetics and in PC clinics were invited to participate via email or a card. Informed consent was completed online.

RESULTS

INHERET aimed to integrate patient data by algorithms based on professional and best practice guidelines to elicit succinct, actionable recommendations that providers can use without affecting clinic workflow or encounter length. INHERET requires a 4th-grade reading level, has simple navigation, and produces data lists and pedigree graphs. Prospective implementation testing revealed understandability of 90% to 100%, ease of use of 85%, and completion rates of 85% to 100%. Physicians using INHERET reported no added time to their encounters when patients were identified for counseling. In a specialty genetics clinic, INHERET's data were input, on average, within 72 hours compared with 4 to 6 weeks through standard care, and the queue for scheduling patients decreased from 400 to fewer than 15 in <6 months.

CONCLUSIONS

INHERET was found to be accessible for all education and age levels, except patients aged >70 years, who encountered more technical difficulties. INHERET aided providers in conveying high-risk status to patients and eliciting appropriate referrals, and, in a specialty clinic, it produced improved workflows and shortened queues.

Accurate Quantification of Monoclonal Immunoglobulins Migrating in the Beta Region on Protein Electrophoresis

BACKGROUND

The concentration of monoclonal immunoglobulins (Igs) in neoplastic monoclonal gammopathic manifestations is generally measured by densitometric scanning of the monoclonal peaks on gel or by measuring absorbance at 210 nm in capillary electrophoresis (CE). For monoclonal Igs migrating in the beta region, measurement is complicated by the major beta-region proteins, namely, transferrin and C3.

METHODS

C3 interference in densitometry was eliminated by heat treatment of serum, and monoclonal Igs were quantified by densitometry of the residual band. The immunochemical measurement of transferrin was converted to its equivalent densitometric quantity. For monoclonal Ig migrating with transferrin, the contribution of the latter was removed by subtracting the converted transferrin concentration from the combined densitometric quantification of the band. With CE, monoclonal Ig was measured by using immunosubtraction (ISUB) to guide demarcation.

RESULTS

The results obtained using the C3 depletion and transferrin subtraction method were lower and yet comparable to the results derived from using CE measurement guided by ISUB. As we expected, the results from both methods were lower than those derived from a perpendicular drop measurement of the peak or via nephelometric assay of the involved isotype.

DISCUSSION

Accurate measurement of monoclonal Igs is important for the diagnosis and monitoring of monoclonal gammopathic manifestations. Determination of serum free light chain concentration per gram of monoclonal Ig is an essential measure for the diagnosis of light chain-predominant multiple myeloma. The method described herein improves accuracy of measurements for monoclonal Igs migrating in the beta region, without the need for special reagents or equipment.

An international multi-center serum protein electrophoresis accuracy and M-protein isotyping study. Part I: factors impacting limit of quantitation of serum protein electrophoresis

Background Serum protein electrophoresis (SPEP) is used to quantify the serum monoclonal component or M-protein, for diagnosis and monitoring of monoclonal gammopathies. Significant imprecision and inaccuracy pose challenges in reporting small M-proteins. Using therapeutic monoclonal antibody-spiked sera and a pooled beta-migrating M-protein, we aimed to assess SPEP limitations and variability across 16 laboratories in three continents. Methods Sera with normal, hypo- or hypergammaglobulinemia were spiked with daratumumab, Dara (cathodal migrating), or elotuzumab, Elo (central-gamma migrating), with concentrations from 0.125 to 10 g/L (n = 62) along with a beta-migrating sample (n = 9). Provided with total protein (reverse biuret, Siemens), laboratories blindly analyzed samples according to their SPEP and immunofixation (IFE) or immunosubtraction (ISUB) standard operating procedures. Sixteen laboratories reported the perpendicular drop (PD) method of gating the M-protein, while 10 used tangent skimming (TS). A mean percent recovery range of 80%-120% was set as acceptable. The inter-laboratory %CV was calculated. Results Gamma globulin background, migration pattern and concentration all affect the precision and accuracy of quantifying M-proteins by SPEP. As the background increases, imprecision increases and accuracy decreases leading to overestimation of M-protein quantitation especially evident in hypergamma samples, and more prominent with PD. Cathodal migrating M-proteins were associated with less imprecision and higher accuracy compared to central-gamma migrating M-proteins, which is attributed to the increased gamma background contribution in M-proteins migrating in the middle of the gamma fraction. There is greater imprecision and loss of accuracy at lower M-protein concentrations. Conclusions This study suggests that quantifying exceedingly low concentrations of M-proteins, although possible, may not yield adequate accuracy and precision between laboratories.

An international multi-center serum protein electrophoresis accuracy and M-protein isotyping study. Part II: limit of detection and follow-up of patients with small M-proteins

Background Electrophoretic methods to detect, characterize and quantify M-proteins play an important role in the management of patients with monoclonal gammopathies (MGs). Significant uncertainty in the quantification and limit of detection (LOD) is documented when M-proteins are <10 g/L. Using spiked sera, we aimed to assess the variability in intact M-protein quantification and LOD across 16 laboratories. Methods Sera with normal, hypo- or hyper-gammaglobulinemia were spiked with daratumumab or elotuzumab, with concentrations from 0.125 to 10 g/L (n = 62) along with a beta-migrating sample (n = 9). Laboratories blindly analyzed samples according to their serum protein electrophoresis (SPEP)/isotyping standard operating procedures. LOD and intra-laboratory percent coefficient of variation (%CV) were calculated and further specified with regard to the method (gel/capillary electrophoresis [CZE]), gating strategy (perpendicular drop [PD]/tangent skimming [TS]), isotyping (immunofixation/immunosubtraction [ISUB]) and manufacturer (Helena/Sebia). Results All M-proteins ≥1 g/L were detected by SPEP. With isotyping the LOD was moderately more sensitive than with SPEP. The intensity of polyclonal background had the biggest negative impact on LOD. Independent of the method used, the intra-laboratory imprecision of M-protein quantification was small (mean CV = 5.0%). Low M-protein concentration and high polyclonal background had the strongest negative impact on intra-laboratory precision. All laboratories were able to follow trend of M-protein concentrations down to 1 g/L. Conclusions In this study, we describe a large variation in the reported LOD for both SPEP and isotyping; overall LOD is most affected by the polyclonal immunoglobulin background. Satisfactory intra-laboratory precision was demonstrated. This indicates that the quantification of small M-proteins to monitor patients over time is appropriate, when subsequent testing is performed within the same laboratory.

Immunofixation to Quantify β2-Transferrin in Cerebrospinal Fluid to Detect Leakage of Cerebrospinal Fluid from Skull Injury

beta 2-Transferrin, the desialated form of transferrin normally found only in cerebrospinal fluid (CSF) and aqueous and vitreous humor, is detected by high-resolution immunofixation (IFE). It is not normally found in nasal or aural fluids, saliva, tears, or serum. Detection in nasal fluid has been suggested to document CSF leakage into the nose after skull injury. We measured beta 2-transferrin in 48 samples of CSF. IFE of the CSF was performed on high-resolution agarose gels and stained with Coomassie Blue. beta 2-Transferrin was estimated by quantifying the total transferrin by rate nephelometry and then determining the percentage of transferrin in the beta 2 vs beta 1 region by densitometric scanning of the IFE pattern. We accurately quantified as little beta 2-transferrin as 2.5 mg/L in the CSF samples. The beta 2-transferrin fraction was clearly visible by IFE at concentrations less than 2.5 mg/L, but accurate quantification was difficult. In the samples assayed, the range of beta 2-transferrin was 4.6 +/- 1.9 mg/L. Use of this technique to examine rhinorrhea in a motor-vehicle-accident patient confirmed leakage of CSF into the nasal cavity through a vent in the left olfactory groove.

Effect of Diabetes Mellitus on Sickle Hemoglobin Quantitation in Sickle Cell Trait

OBJECTIVES

We evaluated the effect of diabetes on sickle hemoglobin (HbS) measurement on two common clinical hemoglobin separation platforms.

METHODS

We performed a method comparison between the Bio-Rad Variant II high-performance liquid chromatography (HPLC) and Sebia Capillarys 2 Flex Piercing capillary electrophoresis (CE) using clinical specimens from 38 patients without hemoglobin variants and 57 patients with sickle cell trait (AS) (HbA1c%, 4.1%-15.4%). We investigated the effect of intermethod Hb% differences on result interpretation by a panel of expert clinical observers.

RESULTS

In diabetic specimens, HPLC undermeasured HbS% up to 7.4% vs CE, due to S1c eluting closely with A0 in HPLC. This increased concern for underlying α-thalassemia in diabetic patients with AS based on HPLC results. HPLC P2% was linearly related to HbA1c% and can be a screen for diabetic AS samples.

CONCLUSIONS

Glycosylation can interfere with HbS% measurement by HPLC. Susceptible specimens should be identified and preferentially analyzed via CE.

A Novel Approach to Estimating M-Protein Concentration: Capillary Electrophoresis Quantitative Immunosubtraction

INTRODUCTION

M-protein quantification is routinely performed by demarcating serum protein electrophoresis (SPE) regions. However, quantification of β-migrating M-protein is hindered by overlapping nonimmunoglobulin protein. Immunosubtraction (ISUB) on capillary electrophoresis is a method currently used qualitatively to subtract out (and therefore highlight) immunoglobulin isotypes in serum, thus reducing the masking effect of normal serum proteins. This study expands on traditional ISUB by developing a quantitative immunosubtraction (qIS) methodology.

METHODS

qIS is achieved by estimating the monoclonal class-specific immunoglobulin contribution to the SPE region containing the M-protein. We conducted a recovery study by use of serial dilutions from 3 patients with β-region M-proteins (n = 22), performing SPE and ISUB on each dilution. We visualized the difference between the ISUB electrophoresis trace and the involved ISUB isotype-subtracted trace to distinguish M-protein and background polyclonal immunoglobulins, which was demarcated independently by 3 pathologists. The M-protein contribution to the β-region was calculated and applied to the β-region protein concentration producing the quantitative M-protein concentration, while minimizing contamination by nonimmunoglobulin or polyclonal immunoglobulin proteins.

RESULTS

Using a quality target of 25% error, we determined that our analytical measurable range spanned the maximum concentration tested (0.81 g/dL) to 0.05 g/dL. Passing-Bablok regression between qIS and the expected M-protein produced a slope of 1.04 (95% CI, 0.94-1.09), r = 0.99. Total CV was 4.8% and intraclass correlation between pathologists was 0.998.

DISCUSSION

qIS promises quantification of β-migrating M-proteins at concentrations an order of magnitude lower than traditional SPE methodology, allowing earlier detection of increasing or decreasing M-protein.

Screening and Diagnosis of Monoclonal Gammopathies: An International Survey of Laboratory Practice

Context.—

Serum tests used for the screening and diagnosis of monoclonal gammopathies include serum protein electrophoresis (SPE; agarose gel or capillary zone), immunofixation (IFE) and immunosubtraction capillary electrophoresis, serum free light chains, quantitative immunoglobulins, and heavy/light–chain combinations. Urine protein electrophoresis and urine IFE may also be used to identify Bence-Jones proteinuria.

Objective.—

To assess current laboratory practice for monoclonal gammopathy testing.

Design.—

In April 2016, a voluntary questionnaire was distributed to 923 laboratories participating in a protein electrophoresis proficiency testing survey.

Results.—

Seven hundred seventy-four laboratories from 38 countries and regions completed the questionnaire (83.9% response rate; 774 of 923). The majority of participants (68.6%; 520 of 758) used agarose gel electrophoresis as their SPE method, whereas 31.4% (238 of 758) used capillary zone electrophoresis. The most common test approaches used in screening were SPE with reflex to IFE/immunosubtraction capillary electrophoresis (39.3%; 299 of 760); SPE only (19.1%; 145 of 760); SPE and IFE or immunosubtraction capillary electrophoresis (13.9%; 106 of 760); and SPE with IFE, serum free light chain, and quantitative immunoglobulins (11.8%; 90 of 760). Only 39.8% (305 of 767) of laboratories offered panel testing for ordering convenience. Although SPE was used by most laboratories in diagnosing new cases of myeloma, when laboratories reported the primary test used to follow patients with monoclonal gammopathy, only 55.7% (403 of 724) chose SPE, with the next most common selections being IFE (18.9%; 137 of 724), serum free light chain (11.7%; 85 of 724), and immunosubtraction capillary electrophoresis (2.1%; 15 of 724).

Conclusions.—

Ordering and testing practices for the screening and diagnosis of monoclonal gammopathy vary widely across laboratories. Improving utilization management and report content, as well as recognition and development of laboratory-directed testing guidelines, may serve to enhance the clinical value of testing.

Transforming Laboratory Utilization Review into Laboratory Stewardship: Guidelines by the PLUGS National Committee for Laboratory Stewardship

Appropriate utilization of clinical laboratory services is important for patient care and requires institutional stewardship. Clinical laboratory stewardship programs are dedicated to improving the ordering, retrieval, and interpretation of appropriate laboratory tests. In addition, these programs focus on developing, maintaining, and improving systems to provide proper financial coverage for medically necessary testing. Overall, clinical laboratory stewardship programs help clinicians improve the quality of patient care while reducing costs to patients, hospitals, and health systems. This document, which was created by a new multiinstitutional committee interested in promoting and formalizing laboratory stewardship, summarizes core elements of successful hospital-based clinical laboratory stewardship programs. The core elements will also be helpful for independent commercial clinical laboratories.

Multiple myeloma and multiple plasmacytomas associated with free gamma heavy chain, free kappa light chain and IgGk paraproteins: an unusual triple gammopathy

Multiple myeloma is a malignant plasma cell dyscrasia that is becoming more prevalent in an increasingly ageing population. It is a complex disease with clinical phases ranging from the premalignant monoclonal gammopathy of undetermined significance to asymptomatic (smouldering) myeloma and then symptomatic myeloma; the latter occasionally terminating in the clonal proliferation of plasma cells outside the bone marrow. We present a patient whose clonally evolved disease from monoclonal gammopathy of undetermined significance to multiple myeloma demonstrated the presence of an unusual combination of monoclonal immunoproteins. Capillary electrophoresis demonstrated the presence of three paraproteins in the gamma region (γ-region), two of which were additional to the IgGk paraprotein which migrated in the slow γ-region at initial diagnosis. Subsequent isotypic identification of the new paraproteins was not possible by immunotyping and initial immunofixation studies failed to definitively characterize the monoclonal proteins. After reduction with beta-mercaptoethanol, two paraproteins were detected by both capillary and gel electrophoresis. However, only immunofixation was able to resolve three distinct monoclonal bands, confirming the presence of free monoclonal kappa light chains in the mid-gamma region and free monoclonal heavy chains in the fast gamma region. Triple gammopathies in themselves are uncommon; this case presents a very unusual combination of paraproteins which required various electrophoretical and immunochemical techniques to identify and characterize them. The change of electrophoretic signature from the monoclonal gammopathy of undetermined significance phase to the diagnosis of multiple myeloma suggested that a number of genetically distinct subclones were present in the pretreatment clonal evolution of the disease.

Detection of Polyclonal Increases in Immunoglobulin G4 Subclass by Distinct Patterns on Capillary Serum Protein Electrophoresis: Diagnostic Pitfalls and Clinical Observations in a Study of 303 Cases

OBJECTIVES

Autoimmunity, hypersensitivity, and the recently recognized set of syndromes collectively termed immunoglobulin G4-related disease (IgG4-RD) may be associated with increased serum IgG4 levels. We reviewed our experience detecting increased IgG4 by distinct serum protein electrophoresis (SPEP) patterns.

METHODS

We studied 303 capillary SPEP cases with dome-like anodal γ changes and increased measured serum IgG4.

RESULTS

IgG4 ranged from 208 to 6,670 mg/dL (normal, <201 mg/dL). Seventeen of 91 cases evaluated by immunosubtraction appeared monotypic (16 κ, 1 λ), but all five cases further analyzed by isoelectric focusing appeared polyclonal. Six cases with markedly increased IgG4 had presumptive evidence of IgG4-RD. Sixteen of 45 assessed patients had autoantibodies.

CONCLUSIONS

Increased polyclonal IgG4 has a characteristic SPEP pattern that may mimic monoclonal gammopathy, even on immunosubtraction. κ Pseudo-restriction might reflect the naturally high κ/λ ratio of the IgG4 subclass. Autoantibodies were common, and the greatest IgG4 increases had clinical features of IgG4-RD.

Challenges of measuring monoclonal proteins in serum

The measurement of monoclonal protein (M-protein) is vital for stratifying risk and following individuals with a variety of monoclonal gammopathies. Direct measurement of the M-protein spike by electrophoresis and immunochemical measurements of specific isotypes or free light chains pairs has provided useful information about the quantity of M-protein. Nonetheless, both traditional electrophoresis and immunochemical methods give poor quantification with M-proteins smaller than 10 g/L (1 g/dL) when in the presence of polyclonal immunoglobulins that co-migrate with the M-protein. In addition, measurements by electrophoresis of M-proteins migrating in the β- and α-regions are contaminated by normal serum proteins in those regions. The most precise electrophoretic method to date for quantification involves exclusion of the polyclonal immunoglobulins by using the tangent skimming method on electropherograms, which provides a 10-fold improvement in precision. So far, however, tangent measurements are limited to γ migrating M-proteins. Another way to improve M-protein measurements is the use of capillary electrophoresis (CE). With CE, one can employ immunosubtraction to select a region of interest in the β region thereby excluding much of the normal proteins from the M-protein measurement. Recent development of an immunochemical method distinguishing heavy/light chain pairs (separately measuring IgGK and IgGL, IgAK and IgAL, and IgMK and IgML) provides measurements that could exclude polyclonal contaminants of the same heavy chain with the uninvolved light chain type. Yet, even heavy/light results contain an immeasurable quantity of polyclonal heavy/light chains of the involved isotype. Finally, use of liquid chromatography-tandem mass spectrometry (LC-MS/MS) looms on the horizon as a means to provide more consistent and sensitive measurements of M-proteins.

Relatively restricted migration of polyclonal IgG4 may mimic a monoclonal gammopathy in IgG4-related disease

OBJECTIVES

IgG4-related disease (IgG4-RD) is an increasingly recognized syndrome of unknown etiology that can affect a wide variety of organs. The commonly shared features include tumor-like swelling of the involved organs, a lymphoplasmacytic infiltrate enriched with polyclonal IgG4-positive plasma cells, variable degree of fibrosis, and elevated serum concentrations of polyclonal IgG4.

METHODS

In a qualitative retrospective study, the electrophoretic characteristics of serum from patients with increased polyclonal IgG4 were studied to see if a reproducible pattern could be identified.

RESULTS

We demonstrate that a characteristic focal band bridging the β and γ fraction by serum protein electrophoresis may be a first serologic indication for IgG4-RD. We further demonstrate that significant κ:λ skewing can occur in the polyclonal IgG4 fraction.

CONCLUSIONS

The focal band detected by electrophoresis in sera from patients with IgG4-RD can be confirmed as polyclonal by immunofixation or immunosubtraction. Because these bands may be predominately of one light chain isotype, they could be misinterpreted as monoclonal gammopathies.

Expression of hemoglobin variant migration by capillary electrophoresis relative to hemoglobin A2 improves precision

We report the precision of the mean migration position of hemoglobin (Hb)S, HbC, HbG (Philadelphia), and HbD (Los Angeles) in 193 samples of whole blood assayed by capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC). By expressing the migration of Hb variants by CE relative to that of HbA(2) in the same sample, there was a significant improvement in the coefficient of variation for each variant studied. The potential usefulness of expressing Hb variants relative to that of HbA(2) was evaluated by comparing the separation of 2 closely migrating Hbs. When expressed by their initial migrations on CE, 25 of the 43 cases of HbG and HbD overlapped. However, when the migrations of these variants were expressed relative to the HbA(2) in the same sample, the 24 cases of HbG separated completely from the 19 cases of HbD. These findings suggest that expressing Hb variants relative to an internal standard, such as HbA(2), may be of value for establishing a library of variant Hbs evaluated by CE.

Responding to large-scale testing errors

Extensive use of automation in the clinical laboratory creates the potential for systematic errors that affect a large number of patient results before the error is discovered. When a large-scale testing error is found, the approaches recommended for responding to individual medical mishaps are often inadequate. This report uses 2 case studies to illustrate some of the unique challenges facing laboratory managers confronted with a large-scale testing error. We identify 9 distinct constituencies that may be impacted by large-scale testing errors, each of which requires laboratory management's thoughtful and timely attention.

The range of hemoglobin A(2) in hemoglobin E heterozygotes as determined by capillary electrophoresis

Capillary electrophoresis (CE) is capable of distinguishing hemoglobin E (HbE) from hemoglobin A(2) (HbA(2)), thus permitting quantification of HbA(2) in patients with HbE. In this study, routine samples submitted for evaluation of hemoglobinopathy that demonstrated HbE were studied by high-pressure liquid chromatography and CE. The data for 52 samples from adult HbE heterozygotes were compared with those for a control group consisting of 209 patients. The mean HbA(2) of patients with HbE trait was 3.4% (SD, 0.4%), which was significantly higher (P < .001) than the 2.6% (SD, 0.4%) for the control group. Seven samples from adults homozygous for HbE were also evaluated. The mean HbA(2) of HbE homozygotes was 4.4%, which was significantly greater (P < .001) than the HbA(2) values for the HbE heterozygotes. Data from these cases provide an estimate of the range of HbA(2) in patients with HbE when evaluated by CE.

Comparison of Sebia Capillarys capillary electrophoresis with the Primus high-pressure liquid chromatography in the evaluation of hemoglobinopathies

The Sebia Capillarys (capillary zone electrophoresis [CE]) and the Primus Resolution high-pressure liquid chromatography (HPLC) were used to prospectively evaluate 297 samples for hemoglobinopathies. Hemoglobin (Hb) A levels were similar on both techniques (mean, 96.2% and SD, 5.7% by CE; mean, 96.8% and SD, 5.5% by HPLC), but HbA2 levels were higher by CE (mean, 2.8%; SD, 0.8%) than by HPLC (mean, 2.3%; SD, 0.8%). HbS had higher values by CE (mean, 40.6%; SD, 18.9%) than by HPLC (mean, 38.4%; SD, 18.9%). In cases with Hg S, HbA2 levels were greater by HPLC (mean, 4.0%; SD, 1.0%) than by CE (mean, 3.1%; SD, 0.8%). HbA2 was occasionally not separated sufficiently from HbC for measurement by CE, but did separate from HbE by CE. Both methods identified HbS, HbC, HbE, HbS, and HbC together, HbA2&prime, HbD-Los Angeles, HbF variant, HbG-Philadelphia, HbS-G Philadelphia, and Hb Lepore.

Hemoglobin Ypsilanti: a high-oxygen-affinity hemoglobin demonstrated by two automated high-pressure liquid chromatography systems

Hemoglobin (Hb) Ypsilanti is a rare high-oxygen-affinity hemoglobin. Like other high-oxygen-affinity hemoglobins, Hb Ypsilanti manifests as erythrocytosis. Because the migration of many high-oxygen-affinity variants on alkaline and acid gels does not differ from that of HbA, oxygen-hemoglobin dissociation studies are often used to document their presence. Hb Ypsilanti is a notable exception because its electrophoresis pattern on alkaline gel is highly characteristic, exemplifying the phenomenon of hybrid formation in variant hemoglobins. In the past few years, several laboratories have begun to use high-pressure liquid chromatography (HPLC) as a screen for hemoglobinopathies. We demonstrate the elution profile of Hb Ypsilanti on the 2 most widely used HPLC methods.

Low IgE monoclonal gammopathy level in serum highlights 20-yr survival in a case of IgE multiple myeloma

This report describes the diagnosis, follow-up, and problems measuring serum immunoglobulin E (IgE) levels in a case of IgE myeloma with 20-yr survival. Serum and urine protein electrophoresis, immunofixation, and the N Latex IgE test were used to characterize the monoclonal proteins. The diagnosis of multiple myeloma in a 56-yr-old man was based on 5.4 g/24 h of monoclonal free lambda chain in urine and bone marrow findings of 23.5% plasma cells (19% mature and 4.5% atypical). IgE lambda monoclonal protein in serum measured 506,000 microg/L (210 833 IU/mL). The lack of other clinical findings of multiple myeloma places this case in the category of 'smoldering or indolent myeloma'. Measurement of serum IgE levels was complicated by the need to predilute serum to avoid antigen excess. Following chemotherapy, the patient went into clinical remission, eventually dying of complications of emphysema. This case expands the recognized clinical spectrum of IgE multiple myeloma.

Serum free light chain (FLC) measurement can aid capillary zone electrophoresis in detecting subtle FLC-producing M proteins

We hypothesized that using a free light chain (FLC) assay as an adjunct to capillary zone electrophoresis (CZE) could improve detection of lymphoplasmacytic processes. We prospectively studied 1,003 consecutive serum samples submitted for routine protein electrophoresis and/or immunofixation electrophoresis by CZE and FLC. Samples from patients previously characterized as having M proteins were excluded. Protein electrophoresis was read by a pathologist unaware of the FLC results. Sixteen cases revealed an abnormal free kappa/lambda ratio in which CZE did not demonstrate an M protein. Nine cases of B-lymphocyte or plasma cell proliferative processes were detected by an abnormal free kappa/lambda ratio in which CZE did not demonstrate an M protein. Cases with low free kappa/lambda ratios included 1 chronic lymphocytic leukemia (CLL), 1 IgM lambda with aplastic anemia, and 1 lambda light chain myeloma. Cases with high free kappa/lambda ratios included 2 CLL, 1 lymphocytosis (possibly early CLL), 1 kappa light chain myeloma, 1 atypical lymphoma with neuropathy, and 1 nonsecretory myeloma. Addition of the free kappa/lambda ratio to CZE increases the yield of lymphocyte and plasma cell proliferative processes detected by 56%.

Antinuclear antibody testing

The ANA test is an excellent screening test for patients with SLE and a few other connective tissue diseases. The LE cell preparation is an assay that is subjective and costly. Because of the presence of a superior screening test (the ANA) and superior specific auto-antibody tests, the author recommends that the use of LE cell preparations be discontinued. ANA screening tests may be performed either by indirect microscopic serology (usually IFA) or EIA. The latter technique is readily automated and many new products for this screening test have appeared in the past decade. The products differ, however, and laboratories are cautioned to test each in the context of the clinical needs of their clinicians. Proper use of the ANA test requires each laboratory to determine the cutoff used under their conditions of assay. Although either ANA screening test has a high negative predictive value in numerous studies, proper selection of patients to be tested is key to improving the predictive value of a positive result. The American College of Rheumatism criteria are reviewed and recommended as part of the patient selection process for this testing.

Comparison of murex single-use diagnostic system with traditional enzyme immunoassay for detection of exposure to human immunodeficiency virus

Because a retrospective study detected 13 negative Western blots out of 38 single-use diagnostic system (SUDS)-positive cases over a 1-year period, we performed a prospective study to compare the performance of the SUDS test with that of enzyme immunoassay (EIA). Of 888 SUDS-tested sera, 875 (98.4%) were both SUDS and EIA negative and 5 (0.6%) were SUDS, EIA, and Western blot positive. The rate of SUDS-positive samples decreased from 3.16/month in the retrospective study to 1.33/month in the prospective study. The immunoassays had sensitivities and specificities of 100 and 99.7 (SUDS) and 100 and 99.4% (traditional EIA), respectively. In laboratories with experienced personnel, the SUDS test performs as well as the EIA as a screen for infection with the human immunodeficiency virus.

Current practices in clinical flow cytometry. A practice survey by the American Society of Clinical Pathologists

The American Society of Clinical Pathologists surveyed 136 laboratories actively engaged in performing clinical flow cytometric testing to determine the demographics of these laboratories, the credentials of the personnel involved with testing, the volume and types of tests performed, and how data are analyzed and interpreted. These results are reported with commentary based on previous surveys and recommended practice guidelines.